Theories differ, but scientists are slowly uncovering clues as to what made the dinosaurs change from turkey-sized reptiles to the giants that have become so familiar. At the moment there is a gap in the fossil record, right in the middle of the Jurassic period, where the transition from small to gigantic seems to have taken place in the dinosaur world.
No one knows exactly how this change took place. Some think that a meteor crash-landed, killing most life forms on Earth so that the survivors had very little competition, and grew to be very large. Others think that as the continents drifted apart, the climate shifted and became more favourable to plants, providing the big lizards with plenty of food and allowing them to grow bigger.
We may soon be able to see what existed in that gap, however. Palaeontologists are working in China’s Gobi Desert and have already uncovered several fossils from the middle of the Jurassic. New species have been discovered, as well as several previously unknown relatives of, for example, our friends the Triceratops and the Stegosaurus. They have even found a mammal-like reptile, which appears to have had fur. Stay tuned— who knows what else they will uncover?